The present invention relates generally to manufacturing execution systems and, more particularly, to a method, system, and computer program product for optimizing throughput of lots.
Computer information management (CIM) systems used in automated IC fabrication facilities (Fabs), such as a facility for processing 300 mm wafers, may include an automated manufacturing execution system (MES), an automated material handling system (AMHS), and an automated real time dispatcher (RTD). In such automated facilities, the basic goals are generally the same: to operate the overall facility with very high degree of efficiency, quality and flexibility, in order to maximize productivity and return-on-investment. Often times, this in turn requires optimizing product mix and output, while minimizing downtime.
While operating in full automation mode (i.e., with no human intervention), these systems produce output with great speed and efficiency. However, these fully automated operations are not without drawbacks. For example, when a production manager needs to stray from the prescribed manufacturing plan, e.g., if a lot requires expedited handling and needs to be processed out of turn ahead of other lots, this typically involves switching the production equipment operations from full automation mode to a manual operation mode, which requires human intervention. In many instances, this switch to manual mode of operation results in disruption and a slow down in production. One solution has been to assign or designate specific equipment for expedited lots (also referred to as ‘rapid turn around time’ (RTAT) lots, ‘quick turn around time’ (QTAT) lots, or ‘hot lots’). However, this solution often results in unnecessary machine down time when there are no expedited lots ready for dispatch.
What is needed, therefore, is a way to optimize the throughput of lots designated for expedited handling in a fully automated production line without switching the equipment out of full automation mode.